An electronic tag (often referred to as an IC tag, an RFID, a radio tag, and an electronic label) is used in physical distribution, production management or the like since it has an advantage that information can be written to a small IC chip.
An electronic tag has a configuration in which a component called an electronic tag inlet having an IC chip (hereinafter referred to as an inlet) is encapsulated and protected with a resin or the like. For example, Patent Document 1 discloses an electronic tag in which an insulating resin sheathing member is formed by injection molding.
Patent Document 2 discloses an example in which a resin material having a high degree of heat resistance such as PPS is used as a thermoplastic resin.
As the method for molding a resin-encapsulated electronic tag, Patent Document 3 states that it is preferable to perform in-mold processing through a protective layer and to place a gate in the middle of the inlet.
On the other hand, Patent Document 4 or 5 discloses a thermoplastic resin composition significantly improved in dimensional stability which can be obtained by filling glass fibers having a flat cross-sectional shape.
Patent Document 6 discloses a resin composition suitable for insert molding by using a thermoplastic elastomer in combination.
Patent Document 1: JP-A-H07-081284
Patent Document 2: JP-A-H08-216576
Patent Document 3: JP-A-2005-332116
Patent Document 4: JP-A-S62-268612
Patent Document 5: JP-A-2003-268252
Patent Document 6: JP-A-2005-161693
In the encapsulation of an electronic tag in a thermoplastic resin composition, conventional encapsulation of a small-sized coil or an IC card, reliability can be attained to some extent with a resin composition for encapsulating which has conventionally been used.
However, it is known that the following problems (a) to (c) may occur, and hence, improvement has been required.    (a) Generation of warpage: If conventional thermoplastic resin compositions are subjected to two-stage molding, an entire molded product suffers a significant degree of warpage, and a problem may occur in which an electronic tag is lifted when installed in articles such as a merchandise;    (b) Insufficient adhesiveness: If conventional thermoplastic resin compositions are subjected to two-stage molding, adhesion between a primary molded product and a secondary molded product may be insufficient, and water may enter through gaps; and    (c) Poor resistance to heat shock: If a heat-resistant film or a glass epoxy substrate is used as a constitution material of an inlet, warpage or opening may occur. In addition, if a resin composition is exposed to thermal stress during molding or a molded product is exposed to thermal stress, large stress is imposed on an inlet.
Therefore, an object of the invention is to provide a resin composition for encapsulating an electronic tag and a resin composition-encapsulated electronic tag which suffers only a slight degree of warpage after molding, exhibits good adhesion between resins in two-stage molding (i.e., exhibits high inlet encapsulation effect), as well as is improved in heat shock resistance.